using let if existingItems is strangely undefined

components/availability/AvailabilityForm.js

@@ -26,7 +26,7 @@ export default function AvailabilityForm({ publisherId, existingItems, inline, o
   };
 
   //coalsce existingItems to empty array
-  existingItems = existingItems || [];
+  let existingItems = existingItems || [];
 
   const [editMode, setEditMode] = useState(existingItems.length > 0);
   const [publisher, setPublisher] = useState({ id: publisherId });